Wraparound extension - size limit - Help!!

18 Apr 2012
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United Kingdom
Hi, Need some urgent advise as we are in the process of submitting an offer and this will help us make an informed decision.

- The house is unextended and is about 23ft wide and 26ft deep
- Rear garden is about 80ft and there is 30ft of space to the side
- The attached neighbour has a 3.5m rear extension (not wraparound)

We want a wrap-around that is 3m to the side and 4.5m to the rear.

An architect I contacted says that wraparound extensions have to be 3m at both side AND rear and a 4.5m rear extension will not be allowed by the council (Harrow Council in NW London). A 4.5m will be allowed without a wrap-around.

Is this true? Assuming neighbours have no problem, is the 3m rear limit for a wraparound extension an absolute limit with no scope for appeal?

If so, we may have to do a 4.5m rear and a 3.5m side separately and not as a wraparound. Will I need planning permission in this case? And can I apply for permission in future to connect them as a wrap-around?

We really want the wraparound though so any advice will be very helpful
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Assuming this is a detached house with full permitted development rights, you can extend 4m deep at the rear x full width. You might be able to increase this to 4.5m deep (or more) subject to a prior notification.
You can extend to the side equal to not more than half the width of the house.
There are no PD rights for wraparound extensions, therefore if you want a wraparound you will need to apply for planning, in which case you can apply for what you want. But there's no guarantee you'll get approval.
Thanks Jeds. It's semi-detached. I wanted to know if there is a hard rule that wrap-arounds cannot be more than 3m on side and rear. That's what my architect says but I don't see that 3m rule anywhere.
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He might be talking about his experience of the LPA - some LPAs do have unwritten 'rules of thumb' - but there is no such rule. For a semi you are restricted to 3m deep rear extension or more with a prior notification. Side extension stays the same.

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